Because most commercially available curable fluoroelastomer gum stocks are not "tacky", sheets of such curable gum stocks do not readily adhere to one another. This lack of tackiness makes it difficult to form rollers from fluoroelastomers using conventional roll-building techniques, which calendered sheets of uncured rubber are wrapped around a mandrel and cured. Two previously reported methods for providing a tacky curable fluoroelastomer gum stock are Italian Pat. No. 815,768, in which shaped, non-vulcanized, fluoroelastomer gum stock is sprayed with an organic liquid having a boiling point above 80.degree. C., and U.S. Pat. No. 4,148,982, in which shaped fluoropolymer gum is thermally modified by heating in the presence of oxygen. Bonding of uncured, shaped fluoroelastomer gum stocks to dissimilar substrates has been carried out using an amino silane primer in methanol or a mixture of amino silane primer and vinyl silane primer in methanol, but these bonding methods require care to prevent voids or delamination due to escape of volatiles during cure, see D. A. Stivers, "Fluorocarbon Rubbers", Rubber Technology, 2d Ed., p. 431 M. Morton, Ed., (Van Nostrand Reinhold Co., New York, 1973).
Also, it is very difficult to repair tears and other damage to cured fluoroelastomer articles such as tank liners and flue ducts. Such repairs can be carried out using epoxy adhesive, see Stivers, id. at 431, but the repaired area will generally lack the thermal and chemical resistance of the undamaged fluoroelastomer.
Low (i.e., curing) amounts of certain fluoro-aliphatic diols have been used as curing components of fluoroelastomer gum stocks. For example, German Offenlegungsschrift No. 28 56 526 and U.S. Pat. No. 4,188,352 describe gum stock compositions containing a fluoropolymer gum, epichlorohydrin gum, an acid acceptor, a curing accelerator (certain tertiary amines, salts of those amines, or certain phosphorous compounds), and a fluorine-containing polyhydroxy compound. The fluorine-containing polyhydroxy compounds said to be useful in such gum stock compositions include the fluoroaliphatic diols HOCH.sub.2 (CF.sub.2).sub.3 CH.sub.2 OH, HOCH.sub.2 CF.sub.2 CFH(CF.sub.2).sub.3 CFHCF.sub.2 CH.sub.2 OH, HOCH.sub.2 CH.sub.2 CH.sub.2 (CF.sub.2).sub.3 CH.sub.2 CH.sub.2 CH.sub.2 OH and HOCH.sub.2 CF.sub.2 CH.sub.2 (CF.sub.2).sub.3 CH.sub.2 CF.sub.2 CH.sub.2 OH. Also, U.S. Pat. No. 4,250,278 describes gum stock compositions comprising a fluoropolymer rubber containing --CH.sub.2 --CF.sub.2 -- units in the polymeric chain, a vulcanizing agent, and a vulcanization accelerator, characterized in that the vulcanizing agent is a fluorine-containing polyhydroxy aliphatic compound, represented by the formula R.sub.f (CH.sub.2 OH).sub.2 wherein R.sub.f is a polyfluoroalkylene or polyfluorochloroalkylene group having 1 to 24 carbon atoms. In each of these 3 references, the amount of fluoroaliphatic diol used is said to be between about 0.5 and 10 parts by weight per one hundred parts of elastomer gum.